Device for injecting a product, in particular for medical use

ABSTRACT

This device comprises: a body housing a hollow injection needle and a container containing the injectable product; the needle is connected to the body but able to move relative to the latter between an injection position and a retracted position; a plunger that slides in the body and is displaceable relative to the latter to perform the injection; said container is able to move relative to the plunger between a position that enables the injection to be performed and a retracted position; means for keeping the needle and the plunger in injection position, which means can be released to free the needle and the plunger to move to said retracted position.

BACKGROUND OF THE INVENTION

The present invention relates to a device for injecting a product,particularly for medical use. This device is particularly designed forperforming an intradermal injection.

In the following description, the terms “proximal” and “distal” areconsidered with reference to the direction in which the product isinjected.

DESCRIPTION OF THE PRIOR ART

Intradermal injections are often performed with conventional syringes,the needle being inserted at a direction forming a slight angle with theskin.

These conventional syringes do not inject completely reliably, nor arethey totally proof against the risk of accidental stabs which can occurafter the injection.

The invention seeks to overcome this fundamental problem.

The object of the invention is therefore to provide a device thatinjects with complete reliability and is totally proof against the riskof accidental stabbing.

SUMMARY OF THE INVENTION

This object is achieved with a device comprising:

a body housing an injection needle and a container containing theinjectable product; the needle is connected to the body but able to moverelative to the latter between an injection position and a retractedposition;

a plunger that slides in the body and is displaceable relative to thelatter to perform the injection; said container is closed at one end andis connected to this plunger but is able to move relative to the latterbetween a position that enables the injection to be performed and aretracted position;

means for keeping the needle in position, which means normally keep theneedle in the injection position and can be released to free the needleto move to said retracted position;

means for keeping the container in position, which means normally keepthe container in the position that enables the injection to beperformed, and can be released to free the container to move to saidretracted position;

a piston engaged in the container and so shaped that, in a firstconfiguration of the piston or relative position of this piston and ofthis container, it closes the container in such a way as to isolate theproduct from the environment outside this container and, in a secondconfiguration of the piston or relative position of this piston and ofthis container, it allows the product to pass out of the container, and

respective means for operating said means of holding the needle inposition and said means of holding the container in position, which, atthe end of the injection, release the means of holding the needle inposition before, or at the same time as, said means of holding thecontainer in position are released.

While the injection is being performed, the needle is kept in theinjection position relative to the body and the container is kept in theinjection position relative to the plunger. The movement of the plungerrelative to the body whereby the closed end of the container is movedtoward the needle moves the piston into said second configuration orposition, allowing the product to pass out of the container.

At the end of the injection, the respective operating means release saidmeans of keeping the needle in position and said means of keeping thecontainer in position. This allows the needle and container to be movedinto the retracted position. This retraction makes the device totallyproof against the risk of accidental stabbing.

The piston may be so shaped that, in said second configuration orposition, it allows the product to pass between itself and thecontainer. The piston may in particular comprise at least one peripheralzone that is able, in said first configuration of the piston, to presstightly against the wall of the container, and, in said secondconfiguration of the piston, to withdraw under the pressure of theinjectable product to allow the latter to pass it.

The piston may also comprise a pierceable zone located in line with theproximal end of the needle. The movement of the container relative tothe needle thus causes the proximal end of the needle to pierce thispierceable zone of the piston so that it comes into communication withthe injectable product and allows this product to flow out through theneedle.

Advantageously, the device comprises spring means for moving the needleand the container to the retracted position without voluntary externalaction.

Advantageously, said body forms a distal wall perpendicular to the axisof the needle, from which the needle projects, in the injectionposition, to a distance equal to the desired depth of insertion of thisneedle during the injection.

This distal wall forms a stop wall designed to be pressed against theskin when the needle is inserted in order to limit its insertion to saiddesired depth.

The device according to the invention is thus particularly suitable forperforming intradermal injections.

In the retracted position, the needle can be simply retracted behindthis wall, in the proximal direction, to eliminate the risk ofaccidental stabbing after injection.

In one possible embodiment of the invention, said means of holding theneedle in position comprise:

a needle-supporting part comprising at least one locking means; and

at least one tab that comprises a locking means able to engage with thatof said needle-supporting part, this tab being moveable radially betweena normal, radially inward position, in which said locking means engagewith each other to keep said needle-supporting part in position relativeto said body, and a radially outward position, in which a zone of theplunger moves this tab radially out to unlock it, thereby freeing saidneedle-supporting part from said body.

In one possible embodiment of the invention, said means of keeping thecontainer in position comprise:

a flange formed at the opposite end of the container from the closed endof this container;

engagement means integral with said plunger for connecting said flangeto the plunger; and

at least one tab comprising said engagement means and able to move inthe radial direction of this plunger between a radially inward position,in which said engagement means connect said flange to the plunger, and aradially outward position, in which said engagement means are withdrawnradially wide of this flange, thereby releasing it.

The accompanying figures illustrate, by way of example, a preferredembodiment of the device according to the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of the invention;

FIG. 2 is an exploded perspective view of the same, in a cross sectionpassing along its axis;

FIG. 3 is a perspective view of the same, in cross section passing alongits axis, in the assembled condition;

FIG. 4 is a partial view, on a larger scale, of its distal end, in crosssection on a plane perpendicular to the cutting plane of FIGS. 2 and 3,with the needle kept in position by means belonging to this device;

FIG. 5 is a view of the device similar to FIG. 4, in a relaxed positionof these means of keeping the needle in position;

FIGS. 6-8 are partial views of the same, on a larger scale, in a crosssection passing along its axis, respectively showing the storageposition, the injection position and the end-of-injection position, and

FIG. 9 shows, on an enlarged scale, a cap belonging to the device.

DESCRIPTION OF THE PREFERRED EMBODIMENT

The figures show a device 1 for injecting a product, particularly formedical use.

As is visible more particularly in FIG. 2, the device 1 comprises a body2, a protective distal cap 3, a hollow injection needle 4, needle 4assembly parts 5 to 7, a spring 8, a plunger 9, a container 10 and apiston 11, all described in detail below.

The body 2 is of a generally tubular shape and comprises a circular ring15 near its distal end.

The cap 3 has wings 20 for holding it by and can be clipped onto a boss21 formed by one of the needle 4 assembly parts 6. As FIG. 9 shows, thiscap 3 may include at least one opening for air to escape through when aportion 26 of the part 6 is inserted into the container 10, as will beseen later. In the embodiment shown in this FIG. 9, the cap 3 hasseveral interrupted ribs 3 a, tiered in the axial direction, withinterruptions which are staggered angularly to form a maze.

The needle 4 is fixed to the part 5. The latter is generally cylindricalin shape and has a groove and a hole which form a flow channelcommunicating with the cavity inside the needle 4.

The part 6 has a tube-shape proximal portion 26 in which the part 5 istightly housed, and comprises a distal hole to allow the needle 4 to beinserted through the boss 21. The portion 26 is designed to be insertedinto the container 10, as mentioned earlier, and comprises a seal 25near its proximal end. This portion 26 thus makes it possible to movethe piston 11 inside the container 10 when the plunger 9 is movedrelative to the body 2, as will be seen later.

The part 6 also includes a flange 27 designed to clip into openings 28(more particularly visible in FIG. 4) in two tabs 29 belonging to thepart 7. These tabs can move radially relative to the latter.

The part 7 is designed to fit tightly into the opening defined by thedistal rib 15 of the body 2, while a distal flange 30 on the part 7 sitsin the distal recess defined by this rib 15. This tight engagementsecures the part 7 to the body 2.

The part 7 also includes an opening through which the boss 21 can passso that the cap 3 can be placed on this boss. This opening is defined bya lip 31, the diameter of which is less than the diameter of the spring8.

As shown in FIG. 4, this lip 31 keeps the spring 8 compressed betweenthe proximal face of this lip 31 and the distal face of the flange 27when the part 6 is clipped onto the part 7.

The part 7 also has walls 32 between the tabs 29. As can be seen inFIGS. 3 and 4, the tabs 29 have internal inclined ramps formed on theirproximal ends while the walls 32 have external inclined ramps formed ontheir proximal ends.

The plunger 9 is engaged in the body 2 and can slide relative to thelatter. It comprises lateral ribs 35 for guiding the sides of thecontainer 10.

At its distal end, the plunger 9 forms two radially moveable tabs 39with internal projections 41 forming stops for receiving a flange 45 onthe container 10. When the flange 45 meets the projections 41, theflange 45 becomes connected to the plunger 9 in the direction in whichthe plunger 9 moves when performing the injection.

The plunger 9 also forms two walls 42 situated between the tabs 39. Ascan be seen in FIGS. 3 and 4, the tabs 39 comprise, at their distalends, internal inclined ramps designed to interact with the ramps of thewalls 32 at the end of the injection stroke, and the walls 42 comprise,at their distal ends, external inclined ramps designed to interact withthe internal ramps on the tabs 29, likewise at the end of the injectionstroke.

At the opposite end from the flange 45, the container 10 comprises abottom 46. The injectable product is contained between the piston 11 andthe walls of the container 10.

The piston 11 is made of a flexible material, especially an elastomer.It is of conical shape and is placed inside the container 10 so that itsface having a smaller surface area is turned toward the injectableproduct. In this way, as FIG. 6 shows, it forms a gap 50 between itselfand the wall of the container 10. The piston 11 also includes a lateralblind hole 51 running most of the way through its thickness, from itsdistal axial face, next to the side wall of the piston 11 defining saidgap 50. The hole 51 is shaped so that it follows this side wall, atleast approximately, and thus defines a peripheral zone occupying aportion of the periphery of the piston 11.

As a comparison of FIGS. 6 and 7 will show, this peripheral zonenormally adopts a radially outward position shown in FIG. 6, in which itpresses tightly against the wall of the container 10, and can adopt aradially inward position shown in FIG. 7, into which it withdraws underthe pressure of the injectable product as the latter passes between thepiston 11 and the container 10, due to the pressure of the piston 11 onthe product.

In practice, the device 1 is initially in the storage position shown inFIG. 6, in which the flange 27 is in engagement with the tabs 29 and theflange 45 is kept in position by the projections 41. In this positionthe needle 4 projects beyond the distal end of the device to the desireddepth for injection, which is an intradermal injection in the exampleillustrated.

The movement of the container 10 with the plunger 9 presses the piston11 against the injectable product, which causes the product to flowbetween the piston 11 and the container 10, as appears in FIG. 7. Theinjection is then performed by continuing the movement of the plunger 9relative to the body 2.

As the plunger reaches the end of the injection stroke, the ramps of thetabs 39 and of the walls 42 bear against the ramps of the walls 32 andof the tabs 29, respectively, with the result that the tabs 29 and 39are displaced toward radially outward positions in which they free theflanges 27 and 45, respectively. The spring 8 can now relax, whichcauses a simultaneous retraction of the parts 5 and 6, and therefore ofthe needle 4, as well as of the container 10 owing to the friction ofthe seal 25, into a retracted position shown in FIG. 8. In this positionthe distal end of the needle 4 is behind the distal face of the part 7and the flange 45 is behind the projections 41, on the proximal side.

It can be seen from the above that the invention makes a number ofcrucial improvements to the corresponding devices of the prior art, bymaking it totally proof against the risk of accidental stabbing whichcan occur after the injection.

It goes without saying that the invention is not limited to theembodiment described above by way of example, but that on the contraryit encompasses all alternative embodiments that come within the scope ofprotection defined by the claims appended hereto. In particular, thepiston may comprise a pierceable zone located in line with the proximalend of the needle, this proximal end projecting from the proximal end ofthe part 5 in which it is held.

1.- A device for injecting a product, particularly for medical use,which comprises: a body housing a hollow injection needle and acontainer containing the injectable product; the needle is connected tothe body but able to move relative to the latter between an injectionposition and a retracted position; a plunger that slides in the body andis displaceable relative to the latter to perform the injection; saidcontainer is closed at one end and is connected to this plunger but isable to move relative to the latter between a position that enables theinjection to be performed and a retracted position; means for keepingthe needle in position, which means normally keep the needle in theinjection position and can be released to free the needle to move tosaid retracted position; means for keeping the container in position,which means normally keep the container in the position that enables theinjection to be performed, and can be released to free the container tomove to said retracted position; a piston engaged in the container andso shaped that, in a first configuration of the piston or relativeposition of this piston and of this container, it closes the containerin such a way as to isolate the product from the environment outsidethis container and, in a second configuration of the piston or relativeposition of this piston and of this container, it allows the product topass out of the container, and respective means for operating said meansof holding the needle in position and said means of holding thecontainer in position, which, at the end of the injection, release themeans of holding the needle in position before, or at the same time as,the means of holding the container in position are released. 2.- Theinjection device as claimed in claim 1, in which the piston is so shapedthat, in said second configuration or position, it allows the product topass between itself and the container. 3.- The injection device asclaimed in claim 2, in which the piston comprises at least oneperipheral zone that is able, in said first configuration of the piston,to press tightly against the wall of the container, and, in said secondconfiguration of the piston, to withdraw under the pressure of theinjectable product to allow the latter to pass it. 4.- The injectiondevice as claimed in claim 1, in which the piston comprises a pierceablezone located in line with the proximal end of the needle. 5.- Theinjection device as claimed in one of claims 1-4, which comprises springmeans for moving the needle and the container to the retracted positionwithout voluntary external action. 6.- The injection device as claimedin one of claims 1-5, in which said body forms a distal wallperpendicular to the axis of the needle, from which the needle projects,in the injection position, to a distance equal to the desired depth ofinsertion of this needle during the injection. 7.- The injection deviceas claimed in one of claims 1-6, in which said means of holding theneedle in position comprise: a needle-supporting part comprising atleast one locking means; and at least one tab that comprises a lockingmeans able to engage with that of said needle-supporting part, this tabbeing moveable radially between a normal, radially inward position, inwhich said locking means engage with each other to keep saidneedle-supporting part in position relative to said body, and a radiallyoutward position, in which a zone of the plunger moves this tab radiallyout to unlock it, thereby freeing said needle-supporting part from saidbody. 8.- The injection device as claimed in one of claims 1-7, in whichsaid means of keeping the container in position comprise: a flangeformed at the opposite end of the container from the closed end of thiscontainer; engagement means integral with said plunger for connectingsaid flange to the plunger; and at least one tab comprising saidengagement means and able to move in the radial direction of thisplunger between a radially inward position, in which said engagementmeans connect said flange to the plunger, and a radially outwardposition, in which said engagement means are withdrawn radially wide ofthis flange, thereby releasing it.